5. A study conducted at a school showed that the batteries used by calculators lasted an average of 110 days with a margin of error of +10 %.
a. What is the minimum average number of days a teacher can expect to have
the batteries last in her classroom?
b. There are roughly 299 days from the first day of school until the last day of
school. The teacher has 24 TI-84 calculators and each one requires 4 triple A
batteries. If the teacher can buy triple A batteries wholesale at 55 cents a battery,
how much do you think she will need to spend at most on batteries for calculators
over the year?

d. 24+-0.114

step-by-step explanation:

the question requires us to calculate the approximate 95% confidence interval for the mean number of ounces of ketchup per bottle in the sample given the following statistics;

sample mean = 24

standard deviation, σ = 0.4

sample size , n = 49

the confidence interval for a population mean is calculated using the formula;

sample mean ± z-score*(σ/sqrt(n))

the z-score associated with a 95% confidence interval, from the standard normal tables, is;

1.96

substituting these values into the formula;

24 ± 1.96*(0.4/7)

= 24 ± 0.112

from the alternatives given, choice d is closest to the above expression;

1) 2/5

2) zero=0/1

3) zero=0/2

4) -4/5

5) undefined=3/0

there is nothing below so i cannot

step-by-step explanation:

ratio is 2 : 9

the answer is three

13.5 : 3